Funding is requested for a 600 MHz NMR spectrometer to support the research of a group of NIH and NSF funded researchers at UCLA. The spectrometer will be located in the UCLA-DOE macromolecular NMR facility. This high field NMR spectrometer will be used to help solve the structures of proteins, nucleic acids, DNA-protein, RNA-protein, and protein-protein complexes proposed for investigation by the major users. The research projects of the five major users are described with the following titles: (1) Structural studies of nucleic acids and complexes (Feigon), (2) Structural studies of proteins and their DNA complexes (Clubb), (3) Structure/Function of Vpr Associated Proteins (Chen), (4) Structural studies of DNA architectural proteins (Johnson), and (5) Structural studies in solution of proteins from pyrobaculum aerophilum and mycobacterium tuberculosis (Eisenberg). This spectrometer is urgently needed to provide adequate high field NMR time for the projects proposed by the major users, as well as to allow additional minor users more access to high field NMR spectrometers for macromolecular studies.